## AA. The Way Out of the Forest

Which way leads out of the forest of Liars & Truth-tellers? This is the first episode on the Mathfactor CD, and the first mathfactor episode podcast to the world!

The Mathfactor is broadcast each Sunday morning on KUAF 91.3 FM, in Fayetteville Arkansas, USA.

In this first segment, we answer a famous puzzle “Which way out of the forest?”. You are in a forest inhabited by liars and truth-tellers; you may ask one question of the person you meet at the fork in the road, to determine which way leads out of the forest. What do you ask?

If you like this puzzle, you will enjoy Raymond Smullyan’s many books, such as The Lady or The Tiger

And we ask a new puzzle: what is the smallest number of marks you need to make on a 12″ rod to be able to measure any number of inches, from 1″ to 12″.

## 1 Comment »

1. ### Sid Hollander said,

January 25, 2011 at 12:33 pm

And we ask a new puzzle: what is the smallest number of marks you need to make on a 12? rod to be able to measure any number of inches, from 1? to 12?.
Answer 1: Single mark at 1″. Then use as dividers
Answer 2: two marks at 3″ and 1′ where
1=1
2=3-1
3=3
4=3+1
5= comp 3, (i.e. 9) -3-1
6= comp 3, (i.e. 9) -3
7= comp 3, (i.e. 9) -3+1
8= comp 3, (i.e. 9) -1
9= comp 3
10= ruler – 3+1
11=ruler -1 1
2=ruler